Vehicle movement dynamics control systems such as the known ESP system, which is described for example in DE 195 15 051 A1, which is incorporated by reference, serve to stabilize a motor vehicle in critical travel situations.
Such systems are usually based on yaw rate control. In this context, the current yaw rate of the vehicle is sensed by means of a yaw rate sensor and compared with a setpoint yaw rate. The setpoint yaw rate is acquired by means of a vehicle model using the vehicle speed and the wheel lock angle set by the driver at the steerable wheels of the vehicle. The vehicle speed and the wheel lock angle are sensed with appropriate sensors. If the difference between the setpoint yaw rate and the measured yaw rate exceeds a threshold value in terms of absolute value, an unstable driving state is detected and the vehicle is stabilized by interventions into the driving behavior.
The stabilizing interventions into the driving behavior comprise braking interventions at individual wheels of the vehicle. In vehicles with hydraulic brake systems, a hydraulic unit which is integrated into the brake system and which permits brake pressure to be built up on a wheel-specific basis is used to carry out the braking interventions. Depending on whether an oversteering or understeering vehicle behavior has been detected, the braking intervention takes place at a front wheel or a rear wheel if the vehicle is a four-wheeled vehicle with two axles.
The described vehicle movement dynamics control system is relatively costly owing to the required sensor system. In addition, the expenditure on the adaptation of controller parameters such as, for example, of the yaw rate threshold value and the determination of the vehicle model of individual vehicles or vehicle types entails relatively high costs.